Coiled dipole antenna

Abstract

An antenna system comprises a transmission member and an antenna at a distal end of the transmission member. The antenna includes a first conductive arm, an insulator extending around the first conductive arm, and a second conductive arm wound around at least a first portion of the insulator to form a second conductive arm coil. A property of the insulator varies along an insulator longitudinal axis of the insulator. The insulator includes a set of formed patterns along at least a portion of the insulator longitudinal axis.

What is claimed is: 
     
       1. An antenna system comprising:
 a transmission member; and 
 an antenna at a distal end of the transmission member, the antenna including a first conductive arm, an insulator extending around the first conductive arm, and a second conductive arm wound around at least a first portion of the insulator to form a second conductive arm coil, wherein a property of the insulator varies along an insulator longitudinal axis, and wherein the insulator includes a set of formed patterns along at least a portion of the insulator longitudinal axis. 
 
     
     
       2. The antenna system of  claim 1  wherein the property of the insulator that varies along the insulator longitudinal axis is an outer profile of the insulator. 
     
     
       3. The antenna system of  claim 2 , wherein the outer profile of the insulator is tapered from an insulator proximal end to an insulator distal portion. 
     
     
       4. The antenna system of  claim 1 , wherein the set of formed patterns vary along the insulator longitudinal axis. 
     
     
       5. The antenna system of claim wherein the set of formed patterns includes at least one of laser-cut slots extending through at least a second portion of the insulator, H-pattern cuts extending through at least a third portion of the insulator, or curved pattern slots. 
     
     
       6. The antenna system of  claim 1 , wherein the set of formed patterns includes at least one groove formed in the insulator. 
     
     
       7. The antenna system of  claim 6 , wherein the at least one groove is shaped to receive the second conductive arm coil. 
     
     
       8. The antenna system of  claim 7 , wherein the insulator includes a plurality of retention features extending from the insulator to maintain the second conductive arm coil within the at least one groove. 
     
     
       9. The antenna system of  claim 7 , wherein the antenna further includes:
 an outer jacket extending around at least a portion of the second conductive arm and the at least a portion of the insulator; and 
 an adhesive material adapted to flow within the at least one groove to form a bond between the outer jacket and the insulator. 
 
     
     
       10. An antenna system comprising:
 a transmission member; and 
 an antenna at a distal end of the transmission member, the antenna including a first conductive arm, an insulator extending around the first conductive arm, and a second conductive arm wound around at least a first portion of the insulator to form a second conductive arm coil, wherein a property of the insulator varies along an insulator longitudinal axis, wherein the insulator includes a first section comprised of a first material and a second section comprised of a second material, and wherein the first section and the second section are positioned at different locations along the insulator longitudinal axis. 
 
     
     
       11. The antenna system of  claim 10 , wherein the insulator further includes a third section comprised of a blend of the first material and the second material, and wherein the third section is positioned between the first section and the second section. 
     
     
       12. An antenna system comprising:
 a transmission member; and 
 an antenna at a distal end of the transmission member, the antenna including
 a first conductive arm, 
 an insulator extending around the first conductive arm, and 
 a second conductive arm wound around at least a portion of the insulator, the second conductive arm forming a second conductive arm coil extending across a transition between the transmission member and the insulator or between the insulator and a distal tip member coupled to a distal end of the insulator, wherein a property of the second conductive arm coil is different at the transition than at the portion of the insulator. 
 
 
     
     
       13. The antenna system of  claim 12 , wherein the property of the second conductive arm coil that is different at the transition than at the portion of the insulator is a pitch of the second conductive arm coil. 
     
     
       14. The antenna system of  claim 13 , wherein the transition is formed where the distal tip member is coupled to a distal section the distal end of the insulator. 
     
     
       15. The antenna system of  claim 14 , wherein the pitch of the second conductive arm coil is smaller at the transition than at the portion of the insulator. 
     
     
       16. The antenna system of  claim 13 , wherein the transition is formed where a distal section of the transmission member meets a proximal end of the insulator, and wherein the pitch of the second conductive arm coil is smaller at the transition than at the portion of the insulator. 
     
     
       17. The antenna system of  claim 13 , wherein the pitch of the second conductive arm coil is at least one of linearly varying, non-linearly varying, logarithmically varying, and varying according to a step function. 
     
     
       18. The antenna system of  claim 12 , wherein the property of the second conductive arm coil that is different at the transition than at the portion of the insulator is at least one of a cross section of a wire forming the second conductive arm coil or a material property of the second conductive arm coil. 
     
     
       19. The antenna system of  claim 12 , wherein an outer profile of the insulator varies along an insulator longitudinal axis of the insulator and wherein the property of the second conductive arm coil that is different at the transition than at the portion of the insulator is a diameter of the second conductive arm coil, the diameter corresponding with the outer profile of the insulator. 
     
     
       20. The antenna system of  claim 12 , wherein the transition is between the transmission member and the insulator.